title: Development of a matrix solid-phase dispersion method for the simultaneous determination of pyrethroid and organochlorinated pesticides in cattle feed.
abstract: A matrix solid-phase dispersion (MSPD) method was developed for the simultaneous extraction of 36 common pesticides and breakdown products (mostly pyrethroids and organochlorines) in cattle feed. Different parameters affecting the extraction efficiency (such as dispersing phase, clean-up adsorbent and elution volume) were investigated. The experimental procedure was optimized using a multivariate statistical approach and the final analyses were carried out by GC-muECD. Several protocols for extract purification were also studied. As far as we know, this is the first application of MSPD for the extraction of most of the target pesticides from animal feed. Using the optimized extraction conditions, the method was validated in terms of accuracy, and precision (within-a-day and among-days), using a certified reference material (CRM 115) as well as spiked cattle feedingstuffs at different concentration levels. A matrix effect study was also carried out using various real samples. The recoveries were satisfactory (>75% in most cases) and the quantification limits, at the sub-ngg(-1) or low-ngg(-1) level, complied with the regulated maximum residue levels (MRLs) in animal feed and in main crops used in the preparation of cattle feeding materials. Finally, the MSPD-GC-muECD methodology was applied to the analysis of real cattle feed samples collected in farms of dairy cattle from NW Spain.
authors.affiliation: Departamento de Quimica Analitica, Nutricion y Bromatologia, Instituto de Investigacion y Analisis Alimentario, Universidad de Santiago de Compostela, Santiago de Compostela 15782, Spain.
authors.forename: Maria
authors.initials: M
authors.lastname: Fernandez-Alvarez
authors.forename: Maria
authors.initials: M
authors.lastname: Llompart
authors.forename: J Pablo
authors.initials: JP
authors.lastname: Lamas
authors.forename: Marta
authors.initials: M
authors.lastname: Lores
authors.forename: Carmen
authors.initials: C
authors.lastname: Garcia-Jares
authors.forename: Rafael
authors.initials: R
authors.lastname: Cela
authors.forename: Thierry
authors.initials: T
authors.lastname: Dagnac
mesh_terms: D000821:Animal Feed / Q000032:analysis*; D000818:Animals; D002417:Cattle; D002849:Chromatography, Gas / Q000379:methods*; D005506:Food Contamination / Q000032:analysis*; D010573:Pesticide Residues / Q000032:analysis*; D011722:Pyrethrins / Q000032:analysis*; D052616:Solid Phase Extraction / Q000379:methods*
chemical_list: D010573:Pesticide Residues; D011722:Pyrethrins